If it was Flu you would feel cold so that you wrap yourself up to raise your core temperature and slow the virus down that way. Apparently it works best at a lower temperature than other viruses.

(I watched a documentary on the Flu virus whilst I had it over Christmas)

Also, of the 3 flu types only Influenza A really wipes you out. B is milder but still shit, C is basically a cold.

(Same American documentary)

Come correct me RL.